The Undoing Project shows a friendship more intense than marriage

The Undoing Project: A Friendship That Changed Our Minds, by Michael Lewis. NORTON

Amos Tversky and Danny Kahneman were an unlikely duo, and during their years as professors of psychology at the Hebrew University in Jerusalem, their students and associates often wondered how “two such radically different personalities could find common ground, much less become soulmates,” writes Michael Lewis in The Undoing Project.

While Danny projected insecurity, Amos exuded confidence. While Danny was a morning person and not terribly sociable, Amos was a night owl and the life of the party. While Danny spent his early years with his family in Europe on the run from the Nazis, Amos was already in the Land of Israel helping to build the Jewish nation.

Yet despite – or perhaps because of – their many differences, they came together in a synergistic burst of creative energy that made them, as the New Yorker noted, “the Lennon and McCartney of social science.” Eventually, their theories about the flawed ways in which people make important decisions would win Amos a $300,000 MacArthur “genius” award and Danny (after Amos’ death) a Nobel prize in economics, among many other prizes.

While both were undeniably brilliant, Amos left an indelible impression on everyone he met. He was small and pale, but agile in an athletic sort of way. “He didn’t look special,” one of his colleagues would recall. “And the way he dressed said nothing. He’d sit there quietly. And then he would open his mouth and speak. And in no time, he became the light that all the butterflies fly to; and in no time, everyone would look up to him wanting to hear what he would say.”

He also had a sharp, memorable wit, of which Lewis provides us with numerous shining examples. Once, an English statistician told him, “I don’t usually like Jews but I like you.” Amos retorted: “I usually like Englishmen but I don’t like you.”

Danny, too, had extraordinary qualities, including the fact that, at 20, he became the Israel Defence Forces’ expert on psychological matters: the system he designed for assessing new recruits has proven so effective that, with only minor adjustments, it is still used today. More than one U.S. Army general has asked a visiting Israeli commander: “Please explain to me how it is possible you guys use the same rifles we use, drive the same tanks we drive, fly the same airplanes we fly, and you are doing so well winning all of the battles and we are not? I know it’s not the weapons. It must be the psychology. How do you pick the soldiers for combat?”

‘And then he would open his mouth and speak…in no time, he became the light that all the butterflies fly to… everyone would look up to him wanting to hear what he would say’

Amos Tversky and Danny Kahneman focused on how people make decisions, and how our biases, misperceptions, intuitive hunches and faulty understanding of the odds colour and distort our judgment. They devised a set of rules of thumb, called heuristics, to help people make better judgments. Their papers, published with obscure names that were hard to make sense of, revolutionized their field and demonstrated time and again that algorithms are usually more reliable than humans when it comes to making important decisions. Their first paper together was titled Belief in the Law of Small Numbers; one of their most famous was called Subjective Probability: A Judgment of Representativeness.

Lewis is the author of a number of popular previous books such as The Big Short, Liar’s Poker and Moneyball, the latter of which was made into a (sadly mediocre) movie starring Brad Pitt. Moneyball tells the story of a professional baseball team owner who devises a new system of choosing baseball players using statistics, thereby assembling a surprisingly efficient and competitive team.

Because it was the Moneyball story that first made Lewis aware of the Tversky-Kahneman collaboration, it is understandable that he opened The Undoing Project with a chapter on how basketball and baseball team owners apply refined statistical models to the task of building superior teams. But this opening threw me for a loop: the book would have been better served with a more germane first chapter that gives a better overview of the subject.

An anecdotal storyteller, Lewis is at his best when describing the unique alchemy between these two legendary figures, whose rapid-fire ideas were so intertwined that even they had trouble discerning whose brain had originated which idea.

“What they were like, in every way but sexually, was lovers,” he writes. “They connected with each other more deeply than either had connected with anyone else.” Even their wives understood that their relationship was “more intense than a marriage.” They would disappear into a seminar room to spark some new thoughts off each other. “From the other side of the door you could sometimes hear them hollering at each other, but the most frequent sound to emerge was laughter.”

Lewis brings in numerous examples of the practical uses of Tversky and Kahneman’s “breathtakingly original studies,” including how doctors (at Toronto’s Sunnybrook Health Sciences Centre in particular) have adapted their findings to help medics make more accurate diagnoses. But readers may find they are still scratching their heads as much at the end of the book as they were at the beginning. The duo’s insights are fascinating and no doubt valuable, but the practical, real-world applications of their discoveries aren’t always made clear.

The book jacket explains: “Their work created the field of behavioural economics, revolutionized Big Data studies, advanced evidence-based medicine, led to a new approach to government regulation, and made much of Michael Lewis’ own work possible.” Unfortunately, the book did not describe all of these accomplishments to this reader’s satisfaction. Science and business nerds will enjoy this book. I am neither, so I admit I was less than enthralled, and sometimes impatient, as I turned its pages.